Utility of protocol kidney biopsies for de novo donor‐specific antibodies

There is limited information about the role of protocol kidney biopsies for de novo donor‐specific antibodies (dnDSA) in kidney transplant recipients, especially in those with stable graft function. We initiated a routine posttransplant DSA monitoring and surveillance biopsy program for dnDSA since 2014. We identified 45 kidney transplant recipients with dnDSA detected between January 2014 and February 2017 who underwent kidney biopsy within 60 days of detection of dnDSA. Twenty‐nine (64%) had stable graft function and 16 (36%) had impaired graft function at the time of dnDSA detection. Even in the group with stable graft function, we found a high rate of rejection (53%) on biopsy. Eighty‐eight percent of patients with impaired graft function had rejection. Those patients with impaired graft function had significantly lower estimated glomerular filtration rate at 12 months postbiopsy and at last follow‐up. Those with impaired graft function had more graft failures; however, this result was not statistically significant. The high rate of asymptomatic rejection, and the fact that outcomes in asymptomatic patients are poor, is in support of the utility of surveillance biopsies in patients with dnDSA.     

Panniculectomy at the time of living donor renal transplantation: An 8‐year experience

Panniculectomy can be performed as a prophylactic procedure preceding transplantation to enable obese patients to meet criteria for renal transplantation. No literature exists on combined renal transplant and panniculectomy surgery (LRT‐PAN). We describe our 8‐year experience performing LRT‐PAN. A retrospective chart review of all patients who had undergone LRT‐PAN from 2010 to 2018 was conducted. Data were collected on patient demographics, allograft survival and function, and postoperative course. Fifty‐eight patients underwent LRT‐PAN. All grafts survived, with acceptable function at 1 year. Median length of stay was 4 days with a mean operative duration of 363 minutes. The wound complication rate was 24%. Ninety‐day readmission rate was 52%, with medical causes as the most common reason for readmission (45%), followed by wound (32%) and graft‐related complications (23%). Body mass index, diabetes status, and previous immunosuppression did not influence wound complication rate or readmission (P = .7720, P = .0818, and P = .4830, respectively). Combining living donor renal transplant and panniculectomy using a multidisciplinary team may improve access to transplantation, particularly for the obese and postobese population. This combined approach yielded shorter‐than‐expected hospital stays and similar wound complication rates, and thus should be considered for patients in whom transplantation might otherwise be withheld on the basis of obesity.     

Primary hyperoxaluria diagnosed after kidney transplant: A review of the literature and case report of aggressive renal replacement therapy and lumasiran to prevent allograft loss

Primary hyperoxaluria type 1 is a rare inherited disorder caused by abnormal liver glyoxalate metabolism leading to overproduction of oxalate, progressive kidney disease, and systemic oxalosis. While the disorder typically presents with nephrocalcinosis, recurrent nephrolithiasis, and/or early chronic kidney disease, the diagnosis is occasionally missed until it recurs after kidney transplant. Allograft outcomes in these cases are typically very poor, often with early graft loss. Here we present the case of a child diagnosed with primary hyperoxaluria type 1 after kidney transplant who was able to maintain kidney function, thanks to aggressive renal replacement therapy as well as initiation of a new targeted therapy for this disease. This case highlights the importance of having a high index of suspicion for primary hyperoxaluria in patients with chronic kidney disease and nephrocalcinosis/nephrolithiasis or with end stage kidney disease of uncertain etiology, as initiating therapies early on may prevent poor outcomes.     

Short‐term adverse effects of early subclinical allograft inflammation in kidney transplant recipients with a rapid steroid withdrawal protocol

The impact of subclinical inflammation (SCI) noted on early kidney allograft biopsies remains unclear. This study evaluated the outcome of SCI noted on 3‐month biopsy. A total of 273/363 (75%) kidney transplant recipients with a functioning kidney underwent allograft biopsies 3‐months posttransplant. Among those with stable allograft function at 3 months, 200 biopsies that did not meet the Banff criteria for acute rejection were identified. These were Group I: No Inflammation (NI, n = 71) and Group II: Subclinical Inflammation (SCI, n = 129). We evaluated differences in kidney function at 24‐months and allograft histology score at 12‐month biopsy. SCI patients had a higher serum creatinine (1.6 ± 0.7 vs 1.38 ± 0.45; P = .02) at 24‐months posttransplant, and at last follow‐up at a mean of 42.5 months (1.69 ± 0.9 vs 1.46 ± 0.5 mg/dL; P = .027). The allograft chronicity score (ci + ct + cg + cv) at 12‐months posttransplant was higher in the SCI group (2.4 ± 1.35 vs 1.9 ± 1.2; P = .02). The incidence of subsequent rejections within the first year in SCI and NI groups was 24% vs 10%, respectively (P = .015). De novo donor‐specific antibody within 12 months was more prevalent in the SCI group (12/129 vs 1/71, P = .03). SCI is likely not a benign finding and may have long‐term implications for kidney allograft function.     

Posttransplant recurrence of calcium oxalate crystals in patients with primary hyperoxaluria: Incidence,risk factors,and effect on renal allograft function

Primary hyperoxaluria (PH) is a metabolic defect that results in oxalate overproduction by the liver and leads to kidney failure due to oxalate nephropathy. As oxalate tissue stores are mobilized after transplantation, the transplanted kidney is at risk of recurrent disease. We evaluated surveillance kidney transplant biopsies for recurrent calcium oxalate (CaOx) deposits in 37 kidney transplants (29 simultaneous kidney and liver [K/L] transplants and eight kidney alone [K]) in 36 PH patients and 62 comparison transplants. Median follow-up posttransplant was 9.2 years (IQR: [5.3, 15.1]). The recurrence of CaOx crystals in surveillance biopsies in PH at any time posttransplant was 46% overall (41% in K/L, 62% in K). Higher CaOx crystal index (which accounted for biopsy sample size) was associated with higher plasma and urine oxalate following transplant (p < .01 and p < .02, respectively). There was a trend toward higher graft failure among PH patients with CaOx crystals on surveillance biopsies compared with those without (HR 4.43 [0.88, 22.35], p = .07). CaOx crystal deposition is frequent in kidney transplants in PH patients. The avoidance of high plasma oxalate and reduction of CaOx crystallization may decrease the risk of recurrent oxalate nephropathy following kidney transplantation in patients with PH. This study was approved by the IRB at Mayo Clinic.     

Economic analysis of screening for subclinical rejection in kidney transplantation using protocol biopsies and noninvasive biomarkers

Subclinical rejection (SCR) screening in kidney transplantation (KT) using protocol biopsies and noninvasive biomarkers has not been evaluated from an economic perspective. We assessed cost-effectiveness from the health sector perspective of SCR screening in the first year after KT using a Markov model that compared no screening with screening using protocol biopsy or biomarker at 3 months, 12 months, 3 and 12 months, or 3, 6, and 12 months. We used 12% subclinical cellular rejection and 3% subclinical antibody-mediated rejection (SC-ABMR) for the base-case cohort. Results favored 1-time screening at peak SCR incidence rather than repeated screening. Screening 2 or 3 times was favored only with age <35 years and with high SC-ABMR incidence. Compared to biomarkers, protocol biopsy yielded more quality-adjusted life years (QALYs) at lower cost. A 12-month biopsy cost $13 318/QALY for the base-case cohort. Screening for cellular rejection in the absence of SC-ABMR was less cost effective with 12-month biopsy costing $46 370/QALY. Screening was less cost effective in patients >60 years. Using biomarker twice or thrice was cost effective only if biomarker cost was <$700. In conclusion, in KT, screening for SCR more than once during the first year is not economically reasonable. Screening with protocol biopsy was favored over biomarkers.     

Absolute quantification of donor‐derived cell‐free DNA as a marker of rejection and graft injury in kidney transplantation: Results from a prospective observational study

Donor‐derived cell‐free DNA (dd‐cfDNA) is a noninvasive biomarker for comprehensive monitoring of allograft injury and rejection in kidney transplantation (KTx). dd‐cfDNA quantification of copies/mL plasma (dd‐cfDNA[cp/mL]) was compared to dd‐cfDNA fraction (dd‐cfDNA[%]) at prespecified visits in 189 patients over 1 year post KTx. In patients (N = 15, n = 22 samples) with biopsy‐proven rejection (BPR), median dd‐cfDNA(cp/mL) was 3.3‐fold and median dd‐cfDNA(%) 2.0‐fold higher (82 cp/mL; 0.57%, respectively) than medians in Stable Phase patients (N = 83, n = 408) without rejection (25 cp/mL; 0.29%). Results for acute tubular necrosis (ATN) were not significantly different from those with biopsy‐proven rejection (BPR). dd‐cfDNA identified unnecessary biopsies triggered by a rise in plasma creatinine. Receiver operating characteristic (ROC) analysis showed superior performance (P = .02) of measuring dd‐cfDNA(cp/mL) (AUC = 0.83) compared to dd‐cfDNA(%) (area under the curve [AUC] = 0.73). Diagnostic odds ratios were 7.31 for dd‐cfDNA(cp/mL), and 6.02 for dd‐cfDNA(%) at thresholds of 52 cp/mL and 0.43%, respectively. Plasma creatinine showed a low correlation (r = 0.37) with dd‐cfDNA(cp/mL). In a patient subset (N = 24) there was a significantly higher rate of patients with elevated dd‐cfDNA(cp/mL) with lower tacrolimus levels (<8 μg/L) compared to the group with higher tacrolimus concentrations (P = .0036) suggesting that dd‐cfDNA may detect inadequate immunosuppression resulting in subclinical graft damage. Absolute dd‐cfDNA(cp/mL) allowed for better discrimination than dd‐cfDNA(%) of KTx patients with BPR and is useful to avoid unnecessary biopsies.     

Differential effects of donor‐specific HLA antibodies in living versus deceased donor transplant

The presence of donor‐specific anti‐HLA antibodies (DSAs) is associated with increased risk of graft failure after kidney transplant. We hypothesized that DSAs against HLA class I, class II, or both classes indicate a different risk for graft loss between deceased and living donor transplant. In this study, we investigated the impact of pretransplant DSAs, by using single antigen bead assays, on long‐term graft survival in 3237 deceased and 1487 living donor kidney transplants with a negative complement‐dependent crossmatch. In living donor transplants, we found a limited effect on graft survival of DSAs against class I or II antigens after transplant. Class I and II DSAs combined resulted in decreased 10‐year graft survival (84% to 75%). In contrast, after deceased donor transplant, patients with class I or class II DSAs had a 10‐year graft survival of 59% and 60%, respectively, both significantly lower than the survival for patients without DSAs (76%). The combination of class I and II DSAs resulted in a 10‐year survival of 54% in deceased donor transplants. In conclusion, class I and II DSAs are a clear risk factor for graft loss in deceased donor transplants, while in living donor transplants, class I and II DSAs seem to be associated with an increased risk for graft failure, but this could not be assessed due to their low prevalence.     

Posttransplant proteinuria due to Apolipoprotein E2 deposition in a kidney allograft

Lipoprotein deposition disorders limited to the kidney and causing proteinuria are rare. We present a case of nephrotic range proteinuria presenting within 4 months after deceased donor renal transplantation in a patient with end-stage kidney disease presumed secondary to hypertension. Two transplant kidney biopsies were performed sixteen weeks after transplantation, and one year after the first biopsy, both showing lipoprotein deposits in the glomeruli, progressive focal segmental glomerulosclerosis, and effacement of visceral foot processes. The patient had a normal lipid profile. Based on previous case reports of Apolipoprotein E variants causing proteinuria in native kidneys, Apolipoprotein E genotyping was performed. Genotyping showed Apolipoprotein E2 homozygosity. This Apolipoprotein E variant has been associated with lipoprotein deposition, proteinuria, and progressive kidney disease in the native kidneys. However, this is the first case of Apolipoprotein E2 homozygosity-related kidney disease in a transplant recipient. The patient was treated with fenofibrate, angiotensin enzyme inhibition, and angiotensin receptor blockade with reduction in proteinuria, and he kept good stable kidney function.     

Robotic kidney transplantation in the obese patient: 10‐year experience from a single center

Despite increasing obesity rates in the dialysis population, obese kidney transplant candidates are still denied transplantation by many centers. We performed a single‐center retrospective analysis of a robotic‐assisted kidney transplant (RAKT) cohort from January 2009 to December 2018. A total of 239 patients were included in this analysis. The median BMI was 41.4 kg/m², with the majority (53.1%) of patients being African American and 69.4% of organs sourced from living donors. The median surgery duration and warm ischemia times were 4.8 hours and 45 minutes respectively. Wound complications (mostly seromas and hematomas) occurred in 3.8% of patients, with 1 patient developing a surgical site infection (SSI). Seventeen (7.1%) graft failures, mostly due to acute rejection, were reported during follow‐up. Patient survival was 98% and 95%, whereas graft survival was 98% and 93%, at 1 and 3 years respectively. Similar survival statistics were obtained from patients undergoing open transplant over the same time period from the UNOS database. In conclusion, RAKT can be safely performed in obese patients with minimal SSI risk, excellent graft function, and patient outcomes comparable to national data. RAKT could improve access to kidney transplantation in obese patients due to the low surgical complication rate.     

Diffuse C4d staining of peritubular capillaries in renal allograft following bamlanivimab therapy

Neutralizing monoclonal antibodies such as bamlanivimab emerged as promising agents in treating kidney transplant recipients with COVID-19. However, the impact of bamlanivimab on kidney allograft histology remains unknown. We report a case of a kidney transplant recipient who received bamlanivimab for COVID-19 with subsequent histologic findings of diffuse peritubular capillary C4d staining. A 33-year-old man with end-stage kidney disease secondary to hypertension who received an ABO compatible kidney from a living donor, presented for his 4-month protocol visit. He was diagnosed with COVID-19 44 days prior to his visit and had received bamlanivimab with an uneventful recovery. His 4-month surveillance biopsy showed diffuse C4d staining of the peritubular capillaries without other features of antibody-mediated rejection (ABMR). Donor-specific antibodies were negative on repeat evaluations. ABMR gene expression panel was negative. His creatinine was stable at 1.3 mg/dl, without albuminuria. Given the temporal relationship between bamlanivimab and our observations of diffuse C4d staining of the peritubular capillaries, we hypothesize that bamlanivimab might bind to angiotensin-converting enzyme 2, resulting in classical complement pathway and C4d deposition. We elected to closely monitor kidney function which has been stable at 6 months after the biopsy. In conclusion, diffuse C4d may present following bamlanivimab administration without any evidence of ABMR.     

Rapid Resolution of Donor‐Derived Glomerular Fibrin Thrombi After Deceased Donor Kidney Transplantation

The aim of this study was to determine the clinical and histologic outcomes related to transplanting kidneys from deceased donors with glomerular fibrin thrombi (GFT). We included all cases transplanted between October 2003 and October 2014 that had either a preimplantation biopsy or an immediate postreperfusion biopsy showing GFT. The study cohort included 61 recipients (9.9%) with GFT and 557 in the control group without GFT. Delayed graft function occurred in 49% of the GFT group and 39% in the control group (p = 0.14). Serum creatinine at 1, 4, and 12 months and estimated GFR at 12 months were similar in the two groups. Estimated 1‐year graft survival was 93.2% in the GFT group and 95.1% in the control group (p = 0.22 by log‐rank). Fifty‐two of the 61 patients in the GFT group (85%) had a 1‐month protocol biopsy, and only two biopsies (4%) showed residual focal glomerular thrombi. At the 1‐year protocol biopsy, the prevalence of moderate to severe interstitial fibrosis and tubular atrophy was 24% in the GFT group and 30% in the control group (p = 0.42). We concluded that GFT resolves rapidly after transplantation and that transplanting selected kidneys from deceased donors with GFT is a safe practice.     

Epidemiology of end‐stage renal failure among twins and diagnosis,management, and current outcomes of kidney transplantation between identical twins

The aim of the study is to provide a comprehensive overview of identical twin kidney transplantation in the modern era. We provide epidemiologic trends in the US twin population from 1959 to 2000, current methods to identify zygosity, outcomes for identical twin transplants, and a comprehensive management strategy for identical twin kidney transplantation. By 2019, we project that 433 010 dizygotic and monozygotic twins will be alive and at risk for developing ESRF. Monozygosity between a donor‐recipient pair can be confirmed by concordance in sex, blood type, and HLA antigen match with precision testing using 13/17 Short Tandem Repeat sequencing to a likelihood of nearly 100%. Among identical twin transplants from 2001 to 2017, excellent patient and kidney graft survival rates were noted. Approximately 50% of kidney transplant recipients of identical twins transplant did not receive maintenance immunosuppression, and no differences in graft survival were noted among patients with and without immunosuppression at 6 and 12 months (P = .8 and .7). Patients with glomerulonephritis as the cause of ESRF had lower graft survival (P = .06) suggesting that recurrent glomerulonephritis as a likely cause of graft loss among these recipients.     

Dietary Approach to Stop Hypertension (DASH) diet and risk of renal function decline and all‐cause mortality in renal transplant recipients

Renal transplant recipients (RTR) are at risk of decline of graft function and premature mortality, with high blood pressure as an important risk factor for both. To study the association of the Dietary Approach to Stop Hypertension (DASH) diet with these adverse events, we conducted a prospective cohort study of adult RTR. Dietary data were collected using a validated 177‐item food frequency questionnaire and an overall DASH‐score was obtained. We included 632 stable RTR (mean ± standard deviation age 53.0 ± 12.7 years, 57% men). Mean DASH score was 23.8 ± 4.7. During median follow‐up of 5.3 (interquartile range, 4.1‐6.0) years, 119 (18.8%) RTR had renal function decline, defined as a combined endpoint of doubling of serum creatinine and death‐censored graft failure, and 128 (20.3%) died. In Cox‐regression analyses, RTR in the highest tertile of the DASH score had lower risk of both renal function decline (hazard ratio [HR] = 0.57; 95% confidence interval [CI], 0.33‐0.96, P = .03) and all‐cause mortality (HR = 0.52; 95%CI, 0.32‐0.83, P = .006) compared to the lowest tertile, independent of potential confounders. Adherence to a DASH‐style diet is associated with lower risk of both renal function decline and all‐cause mortality. These results suggest that a healthful diet might benefit long‐term outcome in RTR.     

Left‐Sided Living Kidney Donation Leads to Transiently Reduced Adrenocortical Responsiveness

Living kidney donation is safe and established, but can lead to long‐term complications such as chronic fatigue. Since the adrenal vein is usually transected during left‐sided donor nephrectomy—which is not necessary on the right—we hypothesized that venous congestion might lead to an impairment of adrenal function, offering a possible explanation. In this prospective open label, monocentric cohort study, adrenal function was compared in left‐ and right‐sided living kidney donors. The primary endpoint was plasma cortisol response to low‐dose adrenocorticotropic hormone (ACTH) stimulation. Secondary endpoints included plasma renin and ACTH concentration as well as adrenal volume in response to donor nephrectomy. A total of 30 healthy donors—20 left‐ and 10 right‐sided donations—were included. On postoperative day 1, response to low‐dose ACTH stimulation was intact, but significantly lower after left‐sided donor nephrectomy. After 28 days, adrenal responsiveness to ACTH stimulation did not differ any longer. Magnetic resonance imaging volumetry showed no significant adrenal volume change over 4 weeks, neither after left‐ nor after right‐sided nephrectomy. In conclusion, left‐sided living kidney donation entails a transiently reduced adrenocortical responsiveness, which returns to baseline after 28 days.     

Karyomegalic interstitial nephritis in a renal allograft

Karyomegalic interstitial nephritis (KIN) is a rare renal interstitial disease entity characterized by large tubular nuclei, accompanied by interstitial inflammation, tubular atrophy, and interstitial fibrosis. Approximately 50 cases of KIN have been described in the native kidney. In this case study, we describe the first case of KIN in a kidney allograft. A 41‐year‐old man presented with declining kidney function and a serum creatinine of 2.7 mg/dL. The native kidney biopsy showed large pleomorphic nuclei in the proximal and distal tubular epithelial cells, which was associated with interstitial inflammation, and extensive interstitial fibrosis and tubular atrophy. Immunohistochemistry for cytomegalovirus, adenovirus, and simian virus 40 were negative. A diagnosis of KIN was rendered. The patient received a living‐related kidney transplant from his sister. At 4‐, 12‐, and 24‐months posttransplant, protocol allograft biopsies showed KIN with large pleomorphic nuclei in the proximal and distal tubules with mild interstitial inflammation, minimal tubular atrophy, and interstitial fibrosis. At 24.7 months of follow‐up, the patient has stable renal function with a serum creatinine of 1.6 mg/dL. The KIN may represent recurrent KIN or donor‐associated KIN. Recognition of this rare disease entity is important as it can be mistaken for a viral infection.     

Inferior long‐term allograft and patient outcomes among recipients of offspring living donor kidneys

While offspring‐to‐parent living donor kidney transplantations may represent an ideal donor–recipient combination to optimize long‐term transplantation outcomes, the sex‐specific long‐term success of these transplantations remains unclear. We hypothesize that allograft and recipient survivals in offspring‐to‐parent living donor kidney transplantation differ between men and women due to donor‐specific alloimmunization during pregnancy. We retrospectively analyzed long‐term allograft and patient survival among men and women who received an offspring living donor kidney compared with those who received other haplotype‐matched living donor kidneys. Based on multivariable Cox proportional hazards modeling of Organ Procurement and Transplantation Network data from 2001 to 2015, we found that both men and women who received offspring living donor kidneys had significantly increased mortality compared with recipients who received nonoffspring living donor kidneys. While male recipients of any living donor kidney had greater risk of mortality and allograft failure than female recipients, there was no significant difference in all‐cause allograft failure or mortality in male versus female recipients of offspring living donor kidney transplantations. Our analysis demonstrated no significant interaction between recipient sex and donor offspring status. We conclude that nonoffspring living donors should be considered whenever feasible for both men and women with multiple donor options.     

Combined Liver–Kidney Transplantation for Primary Hyperoxaluria Type 2: A Case Report

Combined liver/kidney transplant is the preferred transplant option for most patients with primary hyperoxaluria type 1 (PH1) since orthotopic liver transplantation replaces the deficient liver‐specific AGT enzyme, thus restoring normal metabolic oxalate production. However, primary hyperoxaluria type 2 (PH2) is caused by deficient glyoxylate reductase/hydroxypyruvate reductase (GRHPR), and this enzyme is widely distributed throughout the body. Though the relative abundance and activity of GRHPR in various tissues is not clear, some evidence suggests that the majority of enzyme activity may indeed reside within the liver. Thus the effectiveness of liver transplantation in correcting this metabolic disorder has not been demonstrated. Here we report a case of 44‐year‐old man with PH2, frequent stone events, and end‐stage renal disease; he received a combined liver/kidney transplant. Although requiring confirmation in additional cases, the normalization of plasma oxalate, urine oxalate, and urine glycerate levels observed in this patient within a month of the transplant that remain reduced at the most recent follow‐up at 13 months suggests that correction of the GRHPR deficiency in PH2 can be achieved by liver transplantation.     

Kidney recipients with allograft failure,transition of kidney care (KRAFT): A survey of contemporary practices of transplant providers

Kidney allograft failure and return to dialysis carry a high risk of morbidity. A practice survey was developed by the AST Kidney Pancreas Community of Practice workgroup and distributed electronically to the AST members. There were 104 respondents who represented 92 kidney transplant centers. Most survey respondents were transplant nephrologists at academic centers. The most common approach to immunosuppression management was to withdraw the antimetabolite first (73%), while only 12% responded they would withdraw calcineurin inhibitor (CNI) first. More than 60% reported that the availability of a living donor is the most important factor in their decision to taper immunosuppression, followed by risk of infection, risk of sensitization, frailty, and side effects of medications. More than half of respondents reported that embolization was either not available or offered to less than 10% as an option for surgical intervention. Majority reported that ≤50% of failed allograft patients were re-listed before dialysis, and less than a quarter of transplant nephrologists performed frequent visits with their patients with failed kidney allograft after they return to dialysis. This survey demonstrates heterogeneity in the care of patients with a failing allograft and the need for more evidence to guide improvements in clinical practice related to transition of care.